Red squirrels survive in Britain only in isolated strongholds, threatened by squirrelpox virus carried by grey squirrels, with welfare implications for both species in conservation management.
Red squirrel conservation involves difficult welfare trade-offs. The welfare of individual red squirrels dying of squirrelpox - a painful, prolonged illness - is the primary driver of intervention. But conservation management through grey squirrel culling has welfare costs for grey squirrels, which are not responsible for the situation they find themselves in. The development of an oral vaccine for grey squirrels would resolve this tension by protecting red squirrels without lethal grey squirrel control - making it one of the most welfare-positive conservation technologies in development.